The object of such a cutting device is to section the flowing, i.e. moving glass strand by a mechanical cutting operaton. The problem resides in the fact that the temperature of the liquid glass is relatively high so that the cut has to be performed quickly in order to avoid unacceptable heating of the cutting device. This rapid action also is necessary because otherwise the glass strand issuing from the feeding device would become congested. In addition the cut has to be performed neatly so that no glass fibers are pulled or dirtying of the glass occurs.
It is known to use cutting devices for this purpose whose cutting elements are disposed on scissor arms and move in opposite directions while performing the cut. These shear blades are driven mechanically via cam disks, electrically by way of eccentrics or pneumatically by appropriate means.
The disadvantage of this known shear structure is that the glass strand is virtually hacked through, i.e. a quick hit occurs from two sides, which together with the angular shape of the cutting elements cause the glass strand to be separated in a jerky manner. If the glass temperature and thus the deformation properties of the glass are not constant over the cross-sectional area, the resistance to be overcome by the two scissor blades is not exactly the same. Consequently, the penetration speed of one blade changes relatively to that of the other blade so that the glass strand is pressed into the direction of easier deformability. This results in a throw-off of the glass strand or the separated fragments in that direction. As a result the processing on the machine designed to receive the separated fragment becomes much more difficult. Another disadvantage of the known shear structure is the relatively large mass which must be moved with every cut. Thus, limits are imposed a priori upon an increase in the production speed.